Regulatory small RNAs circumvent the conventional quorum sensing pathway in pandemic Vibrio cholerae

1. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 1.

   The V. cholerae QS circuit. HapR-dependent (A) and HapR-independent (B) pathways are controlled by Qrr sRNAs and Hfq. See Introduction for details. Squares, CAI-1; circles, AI-2.

   
   
2. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 2.

   HapR-independent expression of vca0939. Shown is vca0939-lux expression in V. cholerae ^El strains incubated in a 1:1 coculture with either a V. cholerae ^El CAI-1⁻, AI-2⁻ strain (−AIs, open bars) or a V. cholerae ^El CAI-1⁺, AI-2⁺ strain (+AIs, filled bars) (A) and V. cholerae ^El monocultures (B). Each panel shows the mean bioluminescence/OD (Lux/OD) and the standard deviations of triplicate cultures.

   
   
3. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 3.

   Base-pairing between Qrr sRNAs and hapR and vca0939 mRNAs. (A) E. coli carrying either a vector control (open bars) or a qrr1-expressing vector (filled bars), along with a plasmid containing vca0939-lux or the mutagenized reporters vca0939(aa→uu)-lux or vca0939(cc→gg)-lux. (B) MFOLD predictions (18) for mRNA hybrids containing the Qrr sRNA sequence fused by a six-base linker (denoted n) to hapR (Qrr/hapR) or vca0939 (Qrr/vca0939) mRNA. (C) Predicted Qrr/vca0939 duplex showing the location of the vca0939(aa→uu)-lux mutation (arrow under the boxed nucleotides). (D) The predicted inhibitory stem-loop structure in the mRNA of vca0939 showing the location of the vca0939(cc→gg)-lux mutation (arrow adjacent to the boxed nucleotides) (19). In B–D the RBSs are shown in red, the initiation codons are underlined, and the predicted sRNA binding site in the vca0939 mRNA is in blue.

   
   
4. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 4.

   QS occurs in V. cholerae ^Cl strain O395 despite a nonfunctional HapR. (A) qrr-lux (left bars) and vca0939-lux (right bars) expression in V. cholerae ^Cl monocultures. (B) V. cholerae ^Cl CAI-1⁻, AI-2⁻ mutant carrying either qrr-lux (left bars) or vca0939-lux (right bars) in a 1:1 coculture with either a V. cholerae ^Cl CAI-1⁻, AI-2⁻ strain (−AIs, open bars), or a V. cholerae ^Cl CAI-1⁺, AI-2⁺ strain (+AIs, filled bars). Mean bioluminescence/OD (Lux/OD) and the standard deviations of triplicate cultures are shown.